When doing 1KB sequential writes to the same page,
balance_dirty_pages_ratelimited_nr() should be called once instead of 4
times, the latter makes the dirtier tasks be throttled much too heavy.
Fix it with proper de-accounting on clear_page_dirty_for_io().
CC: Chris Mason <chris.mason@xxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
fs/btrfs/file.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- linux-next.orig/fs/btrfs/file.c 2011-08-29 19:14:32.000000000 +0800
+++ linux-next/fs/btrfs/file.c 2011-08-29 19:14:40.000000000 +0800
@@ -1138,7 +1138,8 @@ again:
GFP_NOFS);
}
for (i = 0; i < num_pages; i++) {
- clear_page_dirty_for_io(pages[i]);
+ if (clear_page_dirty_for_io(pages[i]))
+ account_page_redirty(pages[i]);
set_page_extent_mapped(pages[i]);
WARN_ON(!PageLocked(pages[i]));
}
--
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